Ceramics-Silikáty 49 (4) 237-241 (2005)

EFFECT OF TEMPERATURE ON HYDRATION KINETICS AND STABILITY OF HYDRATION PHASES OF METAKAOLIN–LIME SLUDGE–SILICA FUME SYSTEM

M. S. Morsy

This paper presents experimental study to determine the effect of temperature on the hydration kinetics of metakaolin (MK)–lime sludge–silica fume mixture. The kaolin was activated at 800°C for 2 hours. The metakaolin and lime sludge were mixed in a ratio of 1:1. To this mixture, 5 wt.% of silica fume was added to form the final blended composition. The water/binder ratio is 0.93 by weight. The specimens were cured at temperature 20 and 60°C at 100% relative humidity (RH). The phase composition of the formed hydrates was determined by X-ray diffraction and from the thermal analysis (TG and DSC) data. The results showed that the compressive strength of sample cured at 60°C was greater than that cured at 20°C. It is also demonstrated that, the sequence of appearance of hydrated phases at 20°C was CSH, C₂ASH₈ and C₄AH₁₃; while the formed hydrates at 60°C were CSH, C₂ASH₈, C₄AH₁₃ and hydrogarnet (C₃ASH₆).

Keywords: Metakaolin, Lime sludge, Pozzolanic reaction, Curing temperature, Thermal analysis